class Figure(Artist):

    def __str__(self):
        return "Figure(%gx%g)"%(self.figwidth.get(),self.figheight.get())

    def __init__(self,
                 figsize   = None,  # defaults to rc figure.figsize
                 dpi       = None,  # defaults to rc figure.dpi
                 facecolor = None,  # defaults to rc figure.facecolor
                 edgecolor = None,  # defaults to rc figure.edgecolor
                 linewidth = 1.0,   # the default linewidth of the frame
                 frameon = True,    # whether or not to draw the figure frame
                 subplotpars = None, # default to rc
                 ):
        """
        figsize is a w,h tuple in inches
        dpi is dots per inch
        subplotpars is a SubplotParams instance, defaults to rc
        """
        Artist.__init__(self)

        if figsize is None  : figsize   = rcParams['figure.figsize']
        if dpi is None      : dpi       = rcParams['figure.dpi']
        if facecolor is None: facecolor = rcParams['figure.facecolor']
        if edgecolor is None: edgecolor = rcParams['figure.edgecolor']

        self.dpi = Value(dpi)
        self.figwidth = Value(figsize[0])
        self.figheight = Value(figsize[1])
        self.ll = Point( Value(0), Value(0) )
        self.ur = Point( self.figwidth*self.dpi,
                         self.figheight*self.dpi )
        self.bbox = Bbox(self.ll, self.ur)

        self.frameon = frameon

        self.transFigure = get_bbox_transform( unit_bbox(), self.bbox)



        self.figurePatch = Rectangle(
            xy=(0,0), width=1, height=1,
            facecolor=facecolor, edgecolor=edgecolor,
            linewidth=linewidth,
            )
        self._set_artist_props(self.figurePatch)

        self._hold = rcParams['axes.hold']
        self.canvas = None

        if subplotpars is None:
            subplotpars = SubplotParams()

        self.subplotpars = subplotpars

        self._axstack = Stack()  # maintain the current axes
        self.axes = []
        self.clf()

        self._cachedRenderer = None

    def autofmt_xdate(self, bottom=0.2, rotation=30, ha='right'):
        """
        A common use case is a number of subplots with shared xaxes
        where the x-axis is date data.  The ticklabels are often
        long,and it helps to rotate them on the bottom subplot and
        turn them off on other subplots.  This function will raise a
        RuntimeError if any of the Axes are not Subplots.

        bottom : the bottom of the subplots for subplots_adjust
        rotation: the rotation of the xtick labels
        ha : the horizontal alignment of the xticklabels


        """

        for ax in self.get_axes():
            if not hasattr(ax, 'is_last_row'):
                raise RuntimeError('Axes must be subplot instances; found %s'%type(ax))
            if ax.is_last_row():
                for label in ax.get_xticklabels():
                    label.set_ha(ha)
                    label.set_rotation(rotation)
            else:
                for label in ax.get_xticklabels():
                    label.set_visible(False)
        self.subplots_adjust(bottom=bottom)

    def get_children(self):
        'get a list of artists contained in the figure'
        children = [self.figurePatch]
        children.extend(self.axes)
        children.extend(self.lines)
        children.extend(self.patches)
        children.extend(self.texts)
        children.extend(self.images)
        children.extend(self.legends)
        return children

    def contains(self, mouseevent):
#.........这里部分代码省略.........